Power transistors are utilized in a myriad of applications such as in the automotive industry wherein one current carrying electrode of the power transistor may be coupled to an ignition voltage while the other current carrying electrode of the power transistor is coupled to a load that may be intermittently connected thereto.
When a load is connected to the power transistor, current flowing through the power transistor can be sensed by detecting a voltage across a sense resistor that is coupled in series with the power transistor. The drive to the gate electrode of the power transistor can then be adjusted accordingly to control the current. For example, if the voltage across the sense resistor exceeds a predetermined voltage, then the drive to the gate electrode of the power transistor can be reduced.
However, when the load is disconnected from the power transistor, prior art circuitry allows the voltage appearing at the gate electrode of the power transistor to rise to the supply voltage. As a result, when the load is subsequently connected, the power transistor is fully enhanced and a large peak overshoot current flows through the power transistor. This typically results in poor transient performance and may be unacceptable.
Hence, there exists a need for an improved current limit circuit for limiting large peak overshoot current flowing through a power transistor.